Feldstein, Steven B.

Abstract [en]

Extreme large-scale North American cold events are associated with strong undulations in the tropospheric jet stream which bring cold polar air southward over the continent. Here we propose that these jet undulations are associated with the North American part of the Circumglobal Teleconnection Patterna pair of zonally oriented waves of zonal wave number 5 which are in zonal quadrature with each other. While the Pacific/North American pattern is associated with the first circumglobal wave pattern, North American extreme cold events are associated with the second pattern. The 300hPa meridional wind and surface temperature anomalies associated with the Circumglobal North American wave packet are similar to those associated with the strongest eastern U.S. cold events. Both types of events are associated with a wave packet propagating all the way from Asia across the Pacific and across North America, with cold temperature anomalies spreading southeastward from Canada over the continent.